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1.
The metabolic effect of multiple oral testosterone undecanoate (TU) doses over 4 weeks was assessed in seven voluntary men. The protocol was designed to detect accumulation of the substance by choosing the appropriate spot urines collections time and to study the urinary clearance of the substance after weeks of treatment. Urines were analysed by a new GC/C/isotope ratio mass spectrometry (IRMS) method to establish the delta(13)C-values of testosterone metabolites (androsterone and etiocholanolone) together with an endogenous reference compound (16(5alpha)-androsten-3alpha-ol). The significant differences in inter-individual metabolism following TU intake was illustrated by large variations in delta(13)C-values of both T metabolites (maximum Deltadelta(13)C-values = 5.5 per thousand), as well as by very stable longitudinal T/E profiles and carbon isotopic ratios in the first hours following administration. According to T/E ratios and delta(13)C-values, the washout period after 80 mg TU intake was less than 48 h for all subjects and no accumulation phenomenon was observed upon chronic oral administration.  相似文献   

2.
A simple method using liquid chromatography-linear ion trap mass spectrometry for simultaneous determination of testosterone glucuronide (TG), testosterone sulfate (TS), epitestosterone glucuronide (EG) and epitestosterone sulfate (ES) in urine samples was developed. For validation purposes, a urine containing no detectable amount of TG, TS and EG was selected and fortified with steroid conjugate standards. Quantification was performed using deuterated testosterone conjugates to correct for ion suppression/enhancement during ESI. Assay validation was performed in terms of lower limit of detection (1-3ng/mL), recovery (89-101%), intraday precision (2.0-6.8%), interday precision (3.4-9.6%) and accuracy (101-103%). Application of the method to short-term stability testing of urine samples at temperature ranging from 4 to 37 degrees C during a time-storage of a week lead to the conclusion that addition of sodium azide (10mg/mL) is required for preservation of the analytes.  相似文献   

3.
Wang J  Wu M  Liu X  Xu Y 《Steroids》2011,76(14):1560-1565
Androstenedione (4-androstene-3,17-dione) is banned by the World Anti-Doping Agency (WADA) as an endogenous steroid. The official method to confirm androstenedione abuse is isotope ratio mass spectrometry (IRMS). According to the guidance published by WADA, atypical steroid profiles are required to trigger IRMS analysis. However, in some situations, steroid profile parameters are not effective enough to suspect the misuse of endogenous steroids. The aim of this study was to investigate the atypical steroid profile induced by androstenedione administration and the detection of androstenedione doping using IRMS. Ingestion of androstenedione resulted in changes in urinary steroid profile, including increased concentrations of androsterone (An), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5α-diol), and 5β-androstane-3α,17β-diol (5β-diol) in all of the subjects. Nevertheless, the testosterone/epitestosterone (T/E) ratio was elevated only in some of the subjects. The rapid increases in the concentrations of An and Etio, as well as in T/E ratio for some subjects could provide indicators for initiating IRMS analysis only for a short time period, 2-22 h post-administration. However, IRMS could provide positive determinations for up to 55 h post-administration. This study demonstrated that, 5β-diol concentration or Etio/An ratio could be utilized as useful indicators for initiating IRMS analysis during 2-36 h post-administration. Lastly, Etio, with slower clearance, could be more effectively used than An for the confirmation of androstenedione doping using IRMS.  相似文献   

4.
A novel screening procedure for the sulfate and glucuronide conjugates of testosterone (T) and epitestosterone (E) in human urine was developed based on liquid-solid extraction and microbore high-performance liquid chromatography combined on-line with ion-spray tandem mass spectrometry. Confirmation of the sulfate and glucuronide conjugates of testosterone and epitestosterone isolated frrm normal human urine was acheived by selected reaction monitoring of characteristic product ions of the parent compounds. Endogenous levels of the steroid conjugates are detected in normal male urine and an increase is observed when the sample is fortified with authentic analytical standards of the conjugates. Calibration curves of all steroid conjugates in urine are linear over a range of twenty. Deuterated internal standards of testosterone glucuronide and epitestosterone sulfate were used for quantitation of the endogenous conjugates. T/E ratios were determined based on the glucuronide fractions of six replicates from a normal male and were shown to be statistically reproducible and below the accepted T/E threshold of 6:1. Sulfate conjugates were shown to be present at significantly lower levels in the urine. The method has potential as an alternative for monitoring anabolic steroid conjugates in human urin.  相似文献   

5.
In ion trap mass spectrometry, fragile ions may fragment under the application of resonance ejection during precursor mass isolation, reducing MS/MS spectral intensity. In this study the steroidal epimers testosterone glucuronide (TG) and epitestosterone glucuronide (EG) have been chosen as a model for exploring whether compound structure is linked to ion trap fragility. Both compounds form multiple adducts by ESI-MS, namely protonation, ammonium and sodium, however, the mass spectrum of EG displays a more intense ammonium adduct peak than TG. [TG + NH4]+, [EG + NH4]+ and [EG + H]+ were found to be fragile ions. To explain the differences in adduct formation and fragility, molecular modelling was employed. Ammonium adduction was localised to the glucuronide ring oxygens and while EG has eight possible adduction sites, only seven were located for TG explaining the increased ammonium adduct abundance with EG. In EG the bond between the steroid and the glucuronide was slightly longer and the oxygen in this bond was more basic than TG. This shows that the EG bond is weaker which may contribute to the fact that [EG + H]+ but not [TG + H]+ is fragile. To investigate whether stability could be restored by chemical means, EG was derivatised with tris(trimethoxyphenyl)phosphonium chloride or methylated on the carboxylic acid and Girard P or methoxylamine on the 3-keto group. Derivatisation of the steroid rather than the glucuronide eliminated fragility and using a charged derivative eliminated adduct formation. This work demonstrates the importance of carefully considering the nature of the derivative and the site of derivatisation.  相似文献   

6.
Long-term heavy alcohol intake is associated with endocrinological abnormalities the mechanisms of which are still unclear. The objective of the present study was to investigate the effect of alcohol intake on plasma and urine glucocorticoid and androgen steroid levels in healthy premenopausal women using oral contraceptives. In a placebo-controlled interventional study with a cross-over design including nine premenopausal women using oral contraceptives no effect of tolerance was observed with regard to the magnitude of the acute transient alcohol-induced testosterone elevation after a 1-week alcohol drinking period (0.8 g/kg per day). At non-intoxicated time points elevated plasma testosterone and androstenedione levels were found in the afternoon but not in the morning during the alcohol drinking period compared with placebo. An increase in plasma cortisol levels was observed after the discontinuation of alcohol drinking. No effects were observed in total glucocorticoid conjugates in morning urine spot samples. An increase during the alcohol period relative to placebo was, however, observed in the urine etiocholanolone/androsterone, tetrahydrocortisol/allotetrahydrocortisol as well as the 20-hydroxy-/20-ketosteroid ratios. No consistent effect was observed in the urine (tetrahydrocortisol+allotetrahydrocortisol)/tetrahydrocortisone ratio. It is suggested that the alcohol-induced alterations in plasma glucocorticoid and androgen levels during non-intoxicated conditions are due to a change in the hypothalamic-pituitary-adrenal function. The effects observed in the conjugated urine glucocorticoid and androgen ratios are likely to be mediated by a change in the metabolism of these steroids in the liver. The present results may be of relevance in the development of disturbances in the glucocorticoid as well as sex steroid balance among heavy female drinkers.  相似文献   

7.
Tseng YL  Sun CY  Kuo FH 《Steroids》2006,71(9):817-827
Recently, the endogenous origin of nandrolone (19-nortestosterone) and other 19-norsteroids has been a focus of research in the field of drug testing in sport. In the present study, we investigated metabolites conjugated to a glucuronic acid and to a sulfuric acid in urine following administration of four xenobiotic 19-norsteroids. Adult male volunteers administered a single oral dose (10 mg) of each of four 19-norsteroids. Urinary samples collected from 0 to 120 h were subjected to methanolysis and beta-glucuronidase hydrolysis and were derivatized by N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) before gas chromatography-mass spectrometry analysis. We confirmed that 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE) were present in both glucuronide (g) and sulfate (s) conjugates and 19-norepiandrosterone (19-NEA) was excreted exclusively as a sulfate fraction in urine of all 19-norsteroids tested. The overall levels of the three metabolites can be ranked as follows: 19-NA(g+s)>19-NE(g+s)>19-NEA(s). The concentration profiles of these three metabolites in urine peaked between 2 to 12h post-administration and declined thereafter until approximately 72-96 h. 19-NA was most prominent throughout the first 24 h post-administration, except for a case in which an inverse relationship was found after 6h post-administration of nandrolone. Furthermore, we found that sulfate conjugates were present in both 19-NA and 19-NE metabolites in urine of all 19-norsteroids tested. The averaged total amounts of metabolites (i.e. 19-NA(s+g)+19-NE(s+g)+19-NEA(s)) excreted in urine were 38.6, 42.9, 48.3 and 21.6% for nandrolone, 19-nor-4-androsten-3,17-dione, 19-nor-4-androsten-3beta,17beta-diol and 19-nor-5-androstene-3beta,17beta-diol, respectively. Results from the excretion studies demonstrate significance of sulfate-conjugated metabolites on interpretation of misuse of the 19-norsteroids.  相似文献   

8.
We evaluated the levels of (-)-epicatechin (EC) and its metabolites in plasma and urine after intake of chocolate or cocoa by male volunteers. EC metabolites were analyzed by HPLC and LC/MS after glucuronidase and/or sulfatase treatment. The maximum levels of total EC metabolites in plasma were reached 2 hours after either chocolate or cocoa intake. Sulfate, glucuronide, and sulfoglucuronide (mixture of sulfate and glucuronide) conjugates of nonmethylated EC were the main metabolites present in plasma rather than methylated forms. Urinary excretion of total EC metabolites within 24 hours after chocolate or cocoa intake was 29.8 ± 5.3% and 25.3 ± 8.1% of total EC intake. EC in chocolate and cocoa was partly absorbed and was found to be present as a component of various conjugates in plasma, and these were rapidly excreted in urine.  相似文献   

9.
We evaluated the levels of (-)-epicatechin (EC) and its metabolites in plasma and urine after intake of chocolate or cocoa by male volunteers. EC metabolites were analyzed by HPLC and LC/MS after glucuronidase and/or sulfatase treatment. The maximum levels of total EC metabolites in plasma were reached 2 hours after either chocolate or cocoa intake. Sulfate, glucuronide, and sulfoglucuronide (mixture of sulfate and glucuronide) conjugates of nonmethylated EC were the main metabolites present in plasma rather than methylated forms. Urinary excretion of total EC metabolites within 24 hours after chocolate or cocoa intake was 29.8 ± 5.3% and 25.3 ± 8.1% of total EC intake. EC in chocolate and cocoa was partly absorbed and was found to be present as a component of various conjugates in plasma, and these were rapidly excreted in urine.  相似文献   

10.
Synthesis of reference standards is needed to determine the presence and function of steroid glucuronides in the brain or other tissues, because commercial sources of steroid glucuronide standards are limited or unavailable. In the present study porcine, rat, and bovine liver microsomes were tested to evaluate their ability to glucuronidate eight neurosteroids and neuroactive steroids of various types: dehydroepiandrosterone, pregnenolone, isopregnanolone, 5alpha-tetrahydrodeoxycorticosterone, corticosterone, cortisol, beta-estradiol, and testosterone. In general, the glucuronidation efficiency of rat liver was rather poor compared with that of bovine and porcine liver microsomes. Since porcine liver apparently has a relatively large amount of dehydrogenase, its microsomes also produced dehydrogenated steroids and their glucuronides, as well as various regioisomers in which the site of glucuronidation varied. In contrast, bovine liver microsomes produced mainly a single major glucuronidation product and few dehydrogenation products and gave the best overall yield for two-third of the steroids tested. The enzymatic synthesis of five glucuronides of four steroids was carried out and the conditions, purification, and analytical methods for the glucuronidation products were optimized. The steroid glucuronides synthesized were characterized by nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography-mass spectrometry (LC-MS). The stereochemically pure steroid glucuronide conjugates were recovered in milligram amounts (yield 10-78%) and good purity (>85-90%), which is sufficient for LC-MS/MS method development and analyses of steroid glucuronides in biological matrices such as brain, urine, or plasma.  相似文献   

11.
3-Nitrotyrosine (NO(2)Tyr) is a potential biomarker of reactive-nitrogen species (RNS) including peroxynitrite. 3-Nitrotyrosine occurs in human plasma in its free and protein-associated forms and is excreted in the urine. Measurement of 3-nitrotyrosine in human plasma is invasive and associated with numerous methodological problems. Recently, we have described an accurate method based on gas chromatography (GC)-tandem mass spectrometry (MS) for circulating 3-nitrotyrosine. The present article describes the extension of this method to urinary 3-nitrotyrosine. The method involves separation of urinary 3-nitrotyrosine from nitrite, nitrate and l-tyrosine by HPLC, preparation of the n-propyl-pentafluoropropionyltrimethylsilyl ether derivatives of endogenous 3-nitrotyrosine and the internal standard 3-nitro-l-[(2)H(3)]tyrosine, and GC-tandem MS quantification in the selected-reaction monitoring mode under negative-ion chemical ionization conditions. In urine of ten apparently healthy volunteers (years of age, 36.5+/-7.2) 3-nitrotyrosine levels were determined to be 8.4+/-10.4 nM (range, 1.6-33.2 nM) or 0.46+/-0.49 nmol/mmol creatinine (range, 0.05-1.30 nmol/mmol creatinine). The present GC-tandem MS method provides accurate values of 3-nitrotyrosine in human urine at the basal state. After oral intake of 3-nitro-l-tyrosine by a healthy volunteer (27.6 microg/kg body weight) 3-nitro-l-tyrosine appeared rapidly in the urine and was excreted following a biphasic pharmacokinetic profile. Approximately one third of administered 3-nitro-l-tyrosine was excreted within the first 8 h. The suitability of the non-invasive measurement of urinary 3-nitrotyrosine as a method of assessment of oxidative stress in humans remains to be established.  相似文献   

12.
The present study was performed to investigate the influence of the intake of selective oestrogen receptor modulators on the urinary endogenous steroids profile. For this purpose the circadian variability of luteinizing hormone, follicle-stimulating hormone, testosterone, 5α-androstan-3α,17β-diol, 5β-androstan-3α,17β-diol, epitestosterone, 4-androstenedione, androsterone and etiocholanolone were measured on eight subjects (four males and four females) by gas chromatography–mass spectrometry and chemiluminescent immunometric assay techniques before and after oral administration of multiple doses of either tamoxifen (80 mg for 2 days) or toremifene (120 mg for 2 days) or clomiphene (100 mg for 2 days). The individual baseline variability of the steroids studied was set up by collecting the urine samples every 3 h, for 3 days prior to the treatment; whereas the evaluation of the effects of the oral administration of multiple doses of selective oestrogen receptor modulators on the steroid urinary profile was assessed by collecting urine samples every three hours for at least five days from the first administration.The results of our measurements showed that, only in male subjects, the relative urinary concentrations of testosterone, epitestosterone and 4-androstenedione were significantly altered generally after the second day of drug administration. While no significant effects were recorded in both sexes on the luteinizing hormone, follicle-stimulating hormone, androsterone, etiocholanolone, 5α-androstan-3α,17β-diol and 5β-androstan-3α,17β-diol urinary levels and on testosterone/epitestosterone, 5α-androstan-3α,17β-diol/5β-androstan-3α,17β-diol and androsterone/etiocholanolone ratios.  相似文献   

13.
The effects of oral testosterone undecanoate (TU 80 mg; Organon) on plasma testosterone was assessed in 9 men (average age 55 yrs) complaining of loss of sexual interest. Absorption tests were carried out following the first dose of TU and again after 3 or 4 weeks of chronic administration. Absorption was variable in timing, peaks occurring from 30 min to 5 1/2 h after the oral dose. Increases in plasma testosterone of at least 50% of baseline levels occurred in 14 of the 18 tests. Apart from a slightly faster metabolic clearance on the second test, associated with a significant reduction in SHBG, there were no other significant differences between the first and second absorption tests. Variability of absorption may be related to dietary factors. If this can be reduced by dietary control, TU offers distinct advantages over injectable esters and implants in the short-term administration of testosterone to eugonadal men.  相似文献   

14.
19-Norandrosterone (19-NA) as its glucuronide derivative is the target metabolite in anti-doping testing to reveal an abuse of nandrolone or nandrolone prohormone. To provide further evidence of a doping with these steroids, the sulfoconjugate form of 19-norandrosterone in human urine might be monitored as well. In the present study, the profiling of sulfate and glucuronide derivatives of 19-norandrosterone together with 19-noretiocholanolone (19-NE) were assessed in the spot urines of 8 male subjects, collected after administration of 19-nor-4-androstenedione (100 mg). An LC/MS/MS assay was employed for the direct quantification of sulfoconjugates, whereas a standard GC/MS method was applied for the assessment of glucuroconjugates in urine specimens. Although the 19-NA glucuronide derivative was always the most prominent at the excretion peak, inter-individual variability of the excretion patterns was observed for both conjugate forms of 19-NA and 19-NE. The ratio between the glucuro- and sulfoconjugate derivatives of 19-NA and 19-NE could not discriminate the endogenous versus the exogenous origin of the parent compound. However, after ingestion of 100 mg 19-nor-4-androstenedione, it was observed in the urine specimens that the sulfate conjugates of 19-NA was detectable over a longer period of time with respect to the other metabolites. These findings indicate that more interest shall be given to this type of conjugation to deter a potential doping with norsteroids.  相似文献   

15.
Several experimental studies have suggested that diet can alter the production and metabolism of steroids in men. The purpose of this study was to determine the levels of unconjugated steroids and steroid glucuronides as well as sex hormone-binding globulin (SHBG) among normal adult men who were either omnivorous or vegetarians. The participants were white volunteers ranging from 25-35 years of age and the blood samples were taken between 0900 h and 1000 h and between 1600 h and 1700 h for two consecutive days. No significant statistical change was found in plasma dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, dihydrotestosterone and estradiol levels. Vegetarian group showed a higher levels of sex hormone-binding globulin (SHBG) while the free androgen index (FAI; calculated by the ratio testosterone/SHBG) was lower in this group. Although the concentrations of androsterone glucuronide were higher in vegetarian group, the vegetarians had a 25-50% lower level of androstane-3 alpha, 17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide. Our data further indicate that both, androstane-3 alpha,17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide concentrations are significantly correlated with SHBG levels and with the FAI values. The increases in androstane-3 alpha,17 beta-diol glucuronide and androstane-3 beta,17 beta-diol glucuronide levels in the omnivorous group are probably a consequence of the elevation of the FAI. Our data suggest that in a vegetarian group, less testosterone is available for androgenic action.  相似文献   

16.
A sensitive and specific method for the analysis of anisodamine and its metabolites in rat urine by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS) was developed. Various extraction techniques (free fraction, acid hydrolyses and enzyme hydrolyses) and their comparison were carried out for investigation of the metabolism of anisodamine. After extraction procedure the pretreated samples were injected on a reversed-phase C18 column with mobile phase (0.2 ml/min) of methanol/0.01% triethylamine solution (adjusted to pH 3.5 with formic acid) (60:40, v/v) and detected by MS/MS. Identification and structural elucidation of the metabolites were performed by comparing their changes in molecular masses (DeltaM), retention-times and full scan MS(n) spectra with those of the parent drug. At least 11 metabolites (N-demethyl-6beta-hydroxytropine, 6beta-hydroxytropine, tropic acid, N-demethylanisodamine, hydroxyanisodamine, anisodamine N-oxide, hydroxyanisodamine N-oxide, glucuronide conjugated N-demethylanisodamine, sulfate conjugated and glucuronide conjugated anisodamine, sulfate conjugated hydroxyanisodamine) and the parent drug were found in rat urine after the administration of a single oral dose 25mg/kg of anisodamine. Hydroxyanisodamine, anisodamine N-oxide and the parent drug were detected in rat urine for up 95 h after ingestion of anisodamine.  相似文献   

17.
Drug abuse for synthetic anabolic androgenic steroids in order to ameliorate sports results is illegal since the law of june 89 in France. No exception whatsoever, therapeutical purpose(s) included, is accepted. Means for controlling such abuse are reviewed briefly here together with data from our research on epitestosterone modifications following physical exercise and testosterone undecanoate controled administration in 15 nor In France the national body responsible for doping analysis in sports is the «Laboratoire National de Dépistage du Dopage» (LNDD). In fact, the control of drug abuse in sports requires laboratory means enabling the detection of banned substances with unlimited certainty. Briefly, untimed urine samples are analyzed for such purpose by gas (liquid or high pressure) chromatography coupled to mass spectrometry (GC/MS) which is the only technique accepted by the medical commission of I.O. C. and relevant bodies world-wide. However, since testosterone itself can now be used as a mean of steroid abuse in man, detection has to solve new problems arising from such manipulation. After considering various approches in order to prove the offense, such as the isotopic ratio for testosterone and different urinary metabolites, and indirect technique, based on the ratio of testosterone to epitestosterone glucuronides, has proved valuable but is now questionned. Epitestosterone is the 17α epimere of testosterone. It is not readily known to clinicians as it has no androgenic potency [5] and does not bind to the specific plasma protein TeBG (26) or androgen receptor [5, 26]. Epitestosterone was first isolated from human urines, simultaneously, by Brooks [6] and Korenman [18]. Wilson and Lipsett [30] among others demonstrated, in man, that this steroid originated both from adrenals and testis, results confirmed recently by Dehennin [8]. Dray et al. and studied its production and circadian rythm in man pointing out that epitestosterone is found in the sulphate fraction of plasma steroids and in the glucuronide fraction of urinary androgen metabolites [12, 20]. Epitestosterone is recovered as such in urines. It is not metabolized [12, 28]. However the pathway for epitestosterone biosynthesis is still uncertain today. The best (for it’s the only one!) hypothesis at present being that of Weustein et al. [30] who reported that epitestosterone could be synthesyzed in man from Δ5 androstène- 3 β, 17α-diol through a possible non enzymic modification of Δ5 androstène-3β, 17β- diol. Donike et al. [10] showed, in man, that the mean GT/GEPIT ratio in urines was 1,5±0,9 (±SD) using epitestosterone as a marker for endogenous androgens. This added index has being implemented, as an official test for androgen abuse’s detection in sports, since the Los Angeles Olympic Games in 1982. All other parameters being normal the definition of a positive androgen doped case is based on GT/GEPIT values over 6. This value of 6 was obtained by adding 6 SD to the mean obtained in man. However, is the use of this parameter justified and 100% safe? Some have questioned its used arguing that epitestosterone, not a well known substance, can not be reliable and could lead to false positive results. We summarize here the results of the French Research Network to which we participated. Mathian et al. [22] showed that epitestosterone production follows testosterone production whatever the age of the subject. The ratio GT/GEPIT doesn’t vary according to age, even over puberty, it remains at 1,40±0,86 from Tanner Stade II to Tanner Stade V. It doesn’t vary significantly after exercise or with fatigue. We also report our study of 15 young men (18–45 year old) over a year. Extensive blood (T, Δ4, DHT, DHA, SDHA, E2, TeBG, FSH, LH) and urinary parameters (GT, DHT, GEPIT, ADIOL, BDIOL) were measured before, during and after a 21 days course of testosterone undecanoate (TU). Whatever the technique used (GC/MS or RIA) results are identical. We confirmed that GT/GEPIT was very stable for each individual and could be considered as a personnal marker. After TU, at the dosage of 40 to 80 mg/day, GT/GEPIT increased significantly in all instances (athletes and sedentary subjects alike), but not permanently. This change resulted from an increase in testosterone excretion wheras epitestosterone remained non statistically changed. However at the dosage used no permanent modification was found and most of the time GT/GEPIT returned to basal values rapidly. The analysis of the results of our study, according to the limit set by the I.O.C. at 6 for GT/GEPIT, pointed out a lot of false negative (over 50%). Values for GT excretion rate corrected with the creatinine content in the same urinary sample (GT/mg creatinine) have therefore been considered together with GT/GEPIT values. In our opinion, a more suitable and reliable index is thus obtained. The setting of a new limit at 3 for GT/GEPIT (Mean ± 3 SD) together with values under 75 ng/mg creatinine for GT is analyzed. It is also stressed that only a medical commission (aware of the significance of epitestosterone) can interpret the results obtained by analytical chemistry. This is the case in France.  相似文献   

18.
20-Hydroxy-arachidonic acid (20-HETE) was determined in urine by an isotope dilution assay using gas chromatography/mass spectrometry (GC/MS). After addition of 18O2-internal standard, 20-HETE was extracted from urine with hexane either directly or after treatment with glucuronidase. 20-HETE was derivatized to the pentafluorobenzylester and the sample was applied to thin layer chromatography with iso-octane/iso-propanol 9:1 (v/v) as the developing solvent. The corresponding zone was extracted and 20-HETE was hydrogenated. After derivatization to the trimethylsilylether, 20-HETE was determined by GC/MS using the [M-pentafluorobenzyl]- -ion in the negative ion chemical ionization mode. Excretion rates of free and glucuronide conjugated 20-HETE was determined in healthy children and in children with hyperprostaglandin-E-syndrome/antenatal Bartter syndrome (HPS/aBS) with or without indomethacin treatment. Compared to the controls, the HPS/aBS children showed higher excretion rates of 20-HETE, which were suppressed to normal values under indomethacin medication. Free and glucuronide conjugated 20-HETE do not correlate with PGE2 excluding any participation in HPS/aBS.  相似文献   

19.
This study was carried out qualitatively and quantitatively to investigate the presence and the concentrations of anabolic steroids in urine collected from orally administered humans. Microanalysis of conjugated steroids by gas chromatography and mass spectrometry (GC/MS) has been carried out. Following oral administration three major metabolites of anabolic steroid drugs have been detected and partially characterized. The six steroids can be analysed at the same time in 17 min. The lower detection limit was 10 ng/ml in 5 ml of urine. The conjugated steroids from urine were centrifuged to 2,430g for 10 min, the supernatant solution passed through Amberlite XAD-2 column and the steroids eluted fraction esterified by using MSTFA and TMSI. The rate of metabolism and urinary excretion seem to be reasonably fast.  相似文献   

20.
Recently the use of high resolution mass spectrometry or tandem mass spectrometry has enabled the detection of low amounts of anabolic steroids. As a consequence, the post-administration detection time of these drugs has been extended. Recent investigations have shown that norandrosterone, previously unequivocally regarded as evidence of nandrolone administration, might be an endogenous steroid present in small amounts in urine of humans. In this study, very low concentrations (<1 ng/ml) of norandrosterone in urine of a female athlete were detected using tandem mass spectrometry. The presence of norandrosterone was strongly correlated with high plasma 17beta-estradiol levels during the menstrual cycle. Analysis of urine samples from pregnant women supports the hypothesis of formation of precursors for urinary 19-norandrosterone during aromatization of androgens to estrogens. The detection of low urinary concentrations of norandrosterone (0.2-0.5 ng/ml) in samples after strenuous exercise could be regarded as an additional evidence for the existence of such a pathway.  相似文献   

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